nesting and convective systems · project statement: “the current nesting techniques in hwrf and...

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Vijay Tallapragada

NOAA/NWS/NCEP/EMC

Nesting and Convective Systems Update on Team Plans and Activities

Next Generation Global Prediction System

(NGGPS)

HIWPP/NGGPS Program Status Meeting

February 9-10, 2016

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• Chair: Vijay Tallapragada, EMC

• Members: – EMC: Tom Black, Samuel Trahan, Dusan Jovic, Matt Pyle, John

Michalakes, Bin Liu

– AOML: S.G. Gopalakrishnan, Thiago Quirino, Steven Diaz

– GFDL: S.J. Lin, Lucas Harris, Morris Bender, Tim Marchok

– ESRL: Stan Benjamin, Jin Lee, Ligia Bernardet

– NCAR: Bill Skamarock, Chris Davis

– Navy: Jim Doyle

– PSU: David Stensrud, Paul Markowski, Yvette Richardson

– U. Michigan: Christiane Jablonowski, C.M. Zarzycki

NGGPS Nesting/Convective Systems

Team Membership

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• Incorporate more sophisticated nesting or mesh

refinement capabilities in the NEMS framework

• Development of generalized nesting or mesh refinement

techniques

• Implement multiple static and moving nests globally, with

one- and two-way interaction and coupled to other

(ocean, wave, sea ice, land, etc.) models using NEMS

infrastructure

• Implement scale-aware physics appropriate for the high-

resolution nests

• Post-processing, product development and verification of

high-resolution model output


Team Objectives

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• Strategic development approach

– Are the generalized nesting techniques truly independent

of choice of NGGPS dycore(s)?

– How scalable and efficient will be the global models with

two-way interactive nests for operational considerations?

(interactions with overarching system/software

architecture and engineering teams)

– Need for developing appropriate physics and initialization

techniques (interactions with atmospheric physics and

data assimilation teams)

– Need for developing advanced diagnostic and verification

tools for evaluating truly non-hydrostatic model forecasts

at cloud resolving scales


Team Approach

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– Take advantage of already developed (and ongoing

developmental) work in the HWRF and NMMB/NEMS

systems

– Accelerate design and development of efficient two-way

interactive nests using generalized nesting framework

using ESMF/NUOPC coupler functionality in NEMS

– Design of Adaptive Nests that can be activated,

terminated, (or re-activated) during model integration

Near term Challenges

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• Static/moving

• 1-way/2-way interactive (nests)

• Multiple nests run simultaneously

• Bit reproducible and restartable (static/moving/

1-way/2-way )

• Very fast and efficient!

• Dynamics, physics and initialization appropriate

and applicable for high-resolution nests within

the global model

General Requirements for Operational

Nesting or Grid Enhancement

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Generalized Nesting By Coupling

NGGNF can be considered as a subset of the “Coupled NEMS” project. While “Coupled NEMS” focuses on coupling various earth system models through surface interactions, NGGNF is a dynamic interface for nesting that couples one or more atmospheric models at the dynamic level by providing several required numerical transformations across the interface, including 3D interpolations.

NGGNF addresses the shortcomings of the current generation of nesting technology:

1. Offers a high degree of portability and abstraction

• A complete, stand-alone nesting algorithm

• Built into NEMS framework

• No dependence on dynamical core, grid shape, grid projection, or vertical coordinate

2. Offers advanced inter-domain interaction features

• Nests can interact with scale spanning resolution of the parent domain

• Nests can move across domain edges and poles without distortions

• Supports sequential/parallel, 1 and 2-way interactive, domain integration

3. Offers novel features

• Generalized IO: eliminates custom model IO code and performs post-processing

AOML in partnership with EMC and other OAR labs is building the Next Generation Generalized Nesting Framework (NGGNF) within NEMS to advance global-2-local scale modeling for hurricanes

Architecture of the NEMS NUOPC “mediator” with the NGGNF dynamic layer

NGGNF

The Coupled NEMS Project

NGGNF

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Project Statement: “The current nesting techniques in HWRF and NMMB are based on the projection center of the parent grid, limiting their applications

to a confined region in the tropics, and limiting their ability to scale well at higher resolutions and pole-ward locations. A generalized nesting, core

independent nesting technique that can work independent of the parent model’s grid structure as well as map projections will advance the state-of-the-

art in nesting techniques (one-way as well as two-way).

SVN Repository path: https://svnemc.ncep.noaa.gov/projects/hnmmb/branches/AOML-HRD/NGGNF

Current Framework (2016)

NEMS Framework

Example of Core, Grid, and Projection Independent, dynamical (up/)downscaling using and advancing ESMF re-gridding

Model 2 Model 3 Model 5

Model 1

Model 4

Model 3

Model 2

Model 4

Model 5

Example: Generalized Nesting By Coupling

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• Developed a Hurricane NMMB repository at EMC

– Transitioned HIWPP funded Idealized TC framework to repository

https://svnemc.ncep.noaa.gov/projects/hnmmb

– Currently transitioning Basin-scale HWRF multi-storm initialization into NMMB

Configuration

1) Resolution: 18:06:02km,

61 levels, 2mb model top.

2) Initial TC intensity: 20 m/s

at 1002 mb.

3) Physics package: HWRF

with high-frequency calls

Idealized TC Framework in NMMB

Hurricane Developments in NMMB (EMC-HRD Collaborations supported by HIWPP and R2O/NGGPS)

Slide courtesy: Thiago Quirino, HRD/AOML

https://svnemc.ncep.noaa.gov/projects/hnmmb

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Efficiency and Scalability of NMMB (EMC-HRD Collaborations supported by HIWPP and R2O/NGGPS)

• Evaluating NMMB scalability with 2-way nest

interaction

– Performed various timing experiments: 1-way

and 2-way interaction, varying grid sizes,

multiple nests, and HWRF physics package

– Determined that scalability limitations are

similar to those of HWRF:

• Scalability efficiency levels-off as tile size

reaches ~ 12x12 points

• Halo exchanges and collective MPI calls in

solver are costly

• Frequent physics calls (for high resolution

forecasts) are costly

• Forcing and feedback costs are small when

compared to solver costs (low cost of adding

nests)

• Model code must be further optimized and

physics calls must be reduced to attain further

speed-up beyond the saturation point

– Investigating ways to further reduce cost of 2-

way interaction


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Project Statement: “Test and evaluate the Basin-scale HWRF’s multi-storm initialization capabilities

in the NMMB/NEMS framework and assess potential for demonstrating the initialization real-time in

FY16 and implementing it in FY17.”

GFS cold-start

2015-09-03 00Z, MSLP Before Initialization

2015-09-03 00Z, MSLP After Initialization

After

initialization and

relocation

GFS cold-start

After

initialization and

relocation

IGNACIO12E JIMENA13E

SVN Repository path: https://svnemc.ncep.noaa.gov/projects/hnmmb/trunk/sorc/util/vortex_init_b

Multi-Storm Vortex Initialization and

Cycling in NMMB (EMC-HRD Collaborations supported by HIWPP and R2O/NGGPS)

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Evaluation of the Hurricane NMMB (EMC-HRD Collaborations supported by HIWPP and R2O/NGGPS)

• Perform quasi real-time forecasts of Basin-scale NMMB at

18:06:02km resolution for multiple-storms in 2015

– Developed an end-to-end automation system for real-time forecasts

http://storm.aoml.noaa.gov/hnmmb


http://storm.aoml.noaa.gov/hnmmb

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1. The latest HWRF (2015) physics package has been added to

HNMMB, and tested.

2. HWRF moving nest algorithm has been implemented in

HNMMB, and tested

3. HNMMB Restart capability has been implemented.

4. HNNMB can be complied/run using PC-linux-based gfortran.

5. (1) , (2), (3), and (4) have been added to NMMB trunk

6. Post and tracker scripts are working with NMMB, and tested.

7. Rocoto workflow is being built. Main part of it (NPS,

relocation, NMMB, post, tracker) is working now. Lin is still

working on pulling data, and archiving..

8. Start to change NMMB scripts from ksh to python. Keqin is

leading this effort.

Progress of HNMMB at EMC

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Red: HNMMB, no ocean, no DA

Purple: HWRF, no ocean, no DA

Amazing intensity/Pmin forecast from

HNMMB.

Performance of HNMMB for Hurricane

Patricia (2015)

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Old algorithm: difficult to follow storms

when vortex is not well organized or

near islands.

New algorithm: follow the storm

HNNMB Nest motion algorithm

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Options 2014 2015

microphys Fer Fer_hires

shortwave GFDL RRTM

longwave GFDL RRTM

turbulence GFSHUR GFSHUR (updated)

convection SASHUR SASHUR (scale-aware)

Sfc_layer GFDL GFDL

Land_surface GFDL noah

Physics options in HNMMB

Red: a new option or updated

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Vertical X-Z cross section of wind: With 2015 hwrf phys, size and intensity

forecasts improved.

Impact of Physics on Hurricane Structure

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Two-Way Nesting Capabilities in GFDL FV3 (Recent developments using HiRAM and FV3)

Year-long nonhydrostatic HiRAM

simulation using 2005 SSTs, using an 8-

km nest over the tropical Atlantic

Examples of high-resolution

nested grid simulations using

HiRAM and FV3

three-day HiRAM

forecasts of severe

convection during the

Moore, OK tornado

outbreak of May 2013,

in a simulation nesting

down to 1.3 km over

the southern plains

(using HIWPP 3km

global runs)

Slide courtesy: Lucas Harris, GFDL

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Two-Way Nesting Capabilities in GFDL FV3 (Recent developments using HiRAM and FV3)

• Two-way nests in FV3 designed for simultaneous, consistent, coupled

regional and global solutions

Progress since last July:

• Improvements to nested grid algorithm to improve stability and accuracy of

boundary conditions, especially in regions of steep terrain.

• Simple renormalization-based update to ensure conservation of tracer

mass, which can now be conservatively updated to the coarse grid

• Maintenance of bitwise-reproducibility of solutions when changing

processor counts or restarting

• Started experimental sub-seasonal to seasonal (S2S) predictions in HiRAM

using a 8-km nested grid over the tropical Atlantic, based on existing Chen

and Lin seasonal prediction system

Slide courtesy: Lucas Harris, GFDL

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North

American

refinement

MPAS: Mesh Generation: Lloyd’s Method

(iterative, using a user supplied density function)

Equatorial

refinement

Andes

refinement

Slide courtesy: Bill Skamarock, NCAR

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MPAS: Global Mesh and Integration Options

Global Uniform Mesh Global Variable Resolution Mesh Regional Mesh - driven by

(1) previous global MPAS run (no spatial interpolation needed!)

(2) other global model run

(3) analyses

Voronoi meshes allows us to cleanly incorporate both

downscaling and upscaling effects (avoiding the problems in

traditional grid nesting) & to assess the accuracy of the

traditional downscaling approaches used in regional climate

and NWP applications.


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MPAS-Atmosphere 2013-2014-2015

Tropical Cyclone Forecast Experiments

daily 10-day forecasts during the NH tropical cyclone season

Forecast Experiments with Variable-

Resolution Meshes

Western Pacific basin mesh Eastern Pacific basin mesh Atlantic basin mesh


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Mesh Examples for NEPTUNE/NUMA

NEPTUNE: Navy Environmental Prediction sysTem Utilizing the NUMA2 corE

NUMA: Nonhydrostatic Unified Model of the Atmosphere (F. Giraldo NPS)

NEPTUNE-NUMA has a very flexible core that allows for static mesh

refinement, cubed-sphere, icosahedral meshes, limited area meshes.

Slide courtesy: Jim Doyle, NRL

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NEPTUNE-NUMA Adaptive Mesh Refinement

•Non-conforming adaptive mesh

refinement (AMR) capability in

NEPTUNE will increase efficiency

•Possible applications: tropical

cyclones, dispersion, urban,

coastal, severe storms…

E. Hendricks

2-D Rising Bubble 2-D Vortex

Kopera and Giraldo JCP (2013) Slide courtesy: Jim Doyle, NRL

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Variable Resolution Capabilities for NGGPS:

Phase 2 Testing

• Purpose is to demonstrate a baseline capability to provide

enhanced resolution over certain regions of interest, especially

for hurricanes and convective systems

• Approximately a 4:1 variation in horizontal resolution (3 km in

the vicinity of convective systems including hurricanes, up to 13

km in the far field) Individual groups can configure as they

choose, using fixed or moving high-resolution region, 1-way or

2-way nests

• Groups will be required to run the test with GFS physics, but

may submit supplementary tests with their own physics (since

‘scale-aware’ physics may be desirable in this case)

Slide 22 of 31

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NGGPS Nesting Team Milestones and

Deliverables (2015-2016)

• NCEP/AOML: – Transition HIWPP funded upgrades, including ports of the HWRF nest movement

algorithm and idealized tropical cyclone framework into NEMS repository

– Determine the efficiency and scalability of NMMB/NEMS with two-way interactive nests

– Develop, test, and evaluate generalized grid-independent interpolation techniques for

free-standing nests in the NMMB/NEMS framework

– Test and evaluate the basin-scale HWRF multi-storm initialization in NMMB/NEMS

framework and assess potential for demonstrating the initialization real-time in FY16

and implementing it in FY17

– Implement scale-aware physics in NMMB for multi-storm multiple nest applications

– Develop preliminary capabilities for atmosphere-land-ocean-wave coupled system for

hurricane applications

– Proof of concept of global to local scale modeling system for hurricane predictions

• GFDL: – Subseasonal hurricane prediction in a prototype variable-resolution global NGGPS

model

• PSU: – Advancing Storm-Scale Forecasts over Nested Domains for High-Impact Weather

Green: Completed; Red: Ongoing

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• Selected two best cases: 28 April 2014 (153 tornado

reports from Mississippi to Kentucky) and 6 May 2015

(65 tornado reports from Texas to Nebraska) based on

reasonable performance of NAM 4-km nests (location

and timing of CI and subsequent evolution of storms)

• Rerun fire weather nests at 1.33 km resolution (support

from SPC forecasters and Geoff DiMego/Eric Rogers,

EMC)

• Transferred datasets (>2TB) to PSU from EMC

• Developed diagnostic tools to evaluate the case studies

NGGPS Nesting Team: Updates from PSU Advancing Storm-Scale Forecasts over Nested Domains for

High Impact Weather

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• Continue to increase resolution of nests that can operate

at cloud-resolving scales

• Couple nesting capability with more components as

added to NEMS

• Demonstrate global models operating at cloud resolving

scales with high-resolution nests for more accurate

forecasts of significant weather events

• Develop advanced post-processing techniques,

products, verification and diagnostic tools.

• Close interactions with other NGGPS atmospheric

dynamics, physics, data assimilation, overarching

system, software architecture and engineering teams

NGGPS Nesting Team Long-Term

Objectives

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Questions?

nesting and convective systems · project statement: “the current nesting techniques in hwrf and...

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